Professional historians normally focus on military affairs that had a major impact on the societies involved as well as the aftermath of conflicts, while amateur historians and hobbyists often take a larger interest in the details of battles, equipment and uniforms in use.

The essential subjects of military history study are the causes of war, the social and cultural foundations, military doctrine on each side, the logistics, leadership, technology, strategy, and tactics used, and how these changed over time. On the other hand, Just War Theory explores the moral dimensions of warfare, and to better limit the destructive reality caused by war, seeks to establish a doctrine of military ethics.

As an applied field, military history has been studied at academies and service schools because the military command seeks to not repeat past mistakes, and improve upon its current performance by instilling an ability in commanders to perceive historical parallels during a battle, so as to capitalize on the lessons learned from the past.

The discipline of military history is dynamic, changing with development as much of the subject area as the societies and organisations that make use of it.[1] The dynamic nature of the discipline of military history is largely related to the rapidity of change the military forces, and the art and science of managing them, as well as the frenetic pace of technological development that had taken place during the period known as the Industrial Revolution, and more recently in the nuclear and information ages.

An important recent concept is the Revolution in Military Affairs (RMA) which attempts to explain how warfare has been shaped by emerging technologies, such as gunpowder. It highlights the short outbursts of rapid change followed by periods of relative stability.

Historiography is the study of the history and method of the discipline of history or the study of a specialised topic. In this case, military history with an eye to gaining an accurate assessment of conflicts using all available sources. For this reason military history is periodised, creating overlaying boundaries of study and analysis in which descriptions of battles by leaders may be unreliable due to the inclination to minimize mention of failure and exaggerate success. Military historians use Historiographical analysis in an effort to allow an unbiased, contemporary view of records.[2]

One military historian, Jeremy Black, in a recent work mentioned some problems 21st century military historians face as an inheritance of their predecessors: Eurocentricity, a technological bias, a focus on leading military powers and dominant military systems, the separation of land from sea and recently air conflicts, the focus on state-to-state conflict, a lack of focus on political "tasking" in how forces are used.[3]

If these challenges were not sufficient for the military historians, the limits of method are complicated by the lack of records, either destroyed or never recorded for its value as a military secret that may prevent some salient facts from being reported at all; scholars still do not know the exact nature of Greek fire for instance. Despite these limits, wars are some of the most studied and detailed periods of human history.

Military historians have often compared organization, tactical and strategic ideas, leadership, and national support of the militaries of different nations.[4]

The documentation of military history begins with the confrontation between Sumer (current Iraq) and Elam (current Iran) c. 2700 BC near the modern Basra, and includes such enduring records as the Hebrew Bible. Other prominent records in military history are the Trojan War in Homer's Iliad (though its historicity has been challenged), The Histories by Herodotus (484 BC – 425 BC) who is often called the "father of history".[5] Next was Thucydides whose impartiality, despite being an Athenian, allowed him to take advantage of his exile to research the war from different perspectives by carefully examining documents and interviewing eyewitnesses.[6] An approach centered on the analysis of a leader was taken by Xenophon (430 BC - 355 BC) in Anabasis, recording the expedition of Cyrus the Younger into Anatolia.

The nature of warfare never changes, only its superficial manifestations. Joshua and David, Hector and Achilles would recognize the combat that our soldiers and Marines have waged in the alleys of Somalia and Iraq. The uniforms evolve, bronze gives way to titanium, arrows may be replaced by laser-guided bombs, but the heart of the matter is still killing your enemies until any survivors surrender and do your will.

Chariots, pulled by animals like the onager, ox, donkey, and later the horse, originated around 2000 BC. The chariot was an effective, fast weapon; while one man controlled the maneuvering of the chariot, a second bowman could shoot arrows at enemy soldiers. These became crucial to the maintenance of several governments, including the New Egyptian Kingdom and the Shang Dynasty and the nation states of early to mid Zhou dynasty.

Some of the military unit types and technologies which were developed in the ancient world are:

For settled agrarian civilizations, the infantry would become the core of military action. The infantry started as opposing armed groups of soldiers underneath commanders. The Greeks and early Romans used rigid, heavily armed phalanxes. The Macedonians and Hellenistic states would adopt phalanx formations with sarissa pikemen. The Romans would later adopt more flexible maniples from their neighbors which made them extremely successful in the field of battle. The kingdoms of the Warring States in East Asia also adopted infantry combat, a transition from chariot warfare from centuries earlier.

War elephants were often deployed for fighting in ancient warfare. They were first used in India and later adopted by both the Persians and Alexander the Great against one another. War elephants were also used in the Battle of the Hydaspes River, and by Hannibal in the Second Punic War against the Romans.

There were also organizational changes, made possible by better training and intercommunication. Combined arms was the concept of using infantry, cavalry, and artillery in a coordinated way.

Triremes were involved in more complicated sea-land operations. Themistocles helped to build up a stronger Greek navy, composed of 310 ships, and defeated the Persians at the Battle of Salamis, ending the Persian invasion of Greece.[9]

In the First Punic War, the war between Carthage and Rome started with an advantage to Carthage because of their naval experience. A Roman fleet was built in 261 BC, with the addition of the corvus that allowed Roman soldiers on board the ships to board the enemy ships. The bridge would prove effective at the Battle of Mylae, resulting in a Roman victory.

The Vikings, in the 8th century AD, invented a ship propelled by oars with a dragon decorating the prow, hence called the Drakkar. The 12th century AD Song Dynasty invented ships with watertight bulk head compartments while the 2nd century BC Han Dynasty invented rudders and sculled oars for their warships.

Forts were then built out of mud bricks, stones, wood, and other available materials. Romans used rectangular fortresses built out of wood and stone. As long as there have been fortifications, there have been contraptions to break in, dating back to the times of Romans and earlier. Siege warfare is often necessary to capture forts.

Some of the military unit types and technologies which were used in the medieval period are:

Bows and arrows were often used by combatants. Egyptians shot arrows from chariots effectively. The crossbow was developed around 500 BC in China, and was used a lot in the Middle Ages.[11] The English/Welsh longbow from the 12th century also became important in the Middle Ages. It helped to give the English a large early advantage in the Hundred Years' War, even though the English were eventually defeated. The Battle of Crécy and the Battle of Agincourt are excellent examples of how to destroy an enemy using a longbow. It dominated battlefields for over a century.

In the 10th century, the invention of gunpowder led to many new weapons that were improved over time. Black powder was used in China since the 4th century, but it was not used as a weapon until the 11th century.

Until the mid-15th century, guns were held in one hand, while the explosive charge was ignited by the other hand. Then came the matchlock, which was used widely until around the 1720s. Leonardo da Vinci made drawings of the wheel lock which made its own sparks. Eventually, the matchlock was replaced by the flintlock.

Cannons were first used in Europe in the early 14th century, and played a vital role in the Hundred Years' War. The first cannons were simply welded metal bars in the form of a cylinder, and the first cannonballs were made of stone. By 1346, at the Battle of Crécy, the cannon had been used; at the Battle of Agincourt they would be used again.[12]

At the beginning of the 16th century, the first European fire ships were used. Ships were filled with flammable materials, set on fire, and sent to enemy lines. This tactic was successfully used by Francis Drake to scatter the Spanish Armada at the Battle of Gravelines,[13] and would later be used by the Chinese, Russians, Greeks, and several other countries in naval battles.

The Howitzer, a type of field artillery, was developed in the 17th century to fire high trajectory explosive shells at targets that could not be reached by flat trajectory projectiles.

Bayonets also became of wide usage to infantry soldiers. Bayonet is named after Bayonne, France where it was first manufactured in the 16th century. It is used often in infantry charges to fight in hand-to-hand combat. General Jean Martinet introduced the bayonet to the French army. They were used a lot in the American Civil War, and continued to be used in modern wars like the Invasion of Iraq.

Balloons were first used in warfare at the end of the 18th century. It was first introduced in Paris of 1783; the first balloon traveled over 5 miles (8 km). Previously military scouts could only see from high points on the ground, or from the mast of a ship. Now they could be high in the sky, signalling to troops on the ground. This made it much more difficult for troop movements to go unobserved.

Also in the 1860s came the first boats that would later be known as torpedo boats. These were first used in the American Civil War, but generally were not successful. Several Confederates used spar torpedoes, which were bombs on long poles designed to attach to boats. In the later part of the 19th century, the self-propelled torpedo was developed. The HNoMS Rap was the world's first torpedo boat.

At the start of the World Wars, various nations had developed weapons that were a surprise to their adversaries, leading to a need to learn from this, and alter how to combat them. Flame throwers were first used in the First World War. The French were the first to introduce the armored car in 1902. Then in 1918, the British produced the first armored troop carrier. Many early tanks were proof of concept but impractical until further development. In World War I, the British and French held a crucial advantage due to their superiority in tanks; the Germans had only a few dozen A7V tanks, as well as 170 captured tanks. The British and French both had several hundred each. The French tanks included the 13 ton Schneider-Creusot, with a 75 mm gun, and the British had the Mark IV and Mark V tanks.[15]

On December 17, 1903, the Wright Brothers performed the first controlled, powered, heavier-than-air flight; it went 39 meters (120 ft). In 1907, the first helicopter flew, but it wasn't practical for usage. Aviation became important in World War I, in which several aces gained fame. In 1911 an aircraft took off from a warship for the first time. It was a cruiser. Takeoffs were soon perfected, but deck landings on a cruiser were another matter. This led to the development of an aircraft carrier with a decent unobstructed flight deck.

Chemical warfare exploded into the public consciousness in World War I but may have been used in earlier wars without as much human attention. The Germans used gas-filled shells at the Battle of Bolimov on January 3, 1915. These were not lethal, however. In April 1915, the Germans developed a chlorine gas that was highly lethal, and used it to great effect at the Second Battle of Ypres.[16]

During the Cold War, even though fighting did not actually occur, the superpowers – the United States and the USSR – engaged in a race to develop and increase the level of technology available for military purposes. In the space race, both nations attempted to launch human beings into space to the moon. Other technological advances centered on intelligence (like the spy satellite) and missiles (ballistic missiles, cruise missiles). Nuclear submarine, invented in 1955. This meant submarines no longer had to surface as often, and could run more quietly. They evolved into becoming underwater missile platforms. Cruise missiles were invented in Nazi Germany during World War II in the form of the V-1.

The influence of technology on military history, and evident Eurocentrism are nowhere more pronounced than in the attempt by the military historians to divide their subject area into more manageable periods of analysis. While general discipline of history subdivides history into Ancient history (Classical antiquity), Middle Ages (Europe, 4th century – 15th century), Early Modern period (Europe, 14th century – 18th century), Modern era (Europe, 18th century – 20th century), and the Post-Modern (USA, 1949–present), the periodisation below stresses technological change in its emphasis, particularly the crucial dramatic change during the Gunpowder warfare period.

Periodisation is not uniformly applied through time and space, affirming the claims of Eurocentrism from regional historians. For example, what might be described as prehistoric warfare is still practised in a few parts of the world. Other eras that are distinct in European history, such as the era of medieval warfare, may have little relevance in East Asia.

Much of what we know of ancient history is the history of militaries: their conquests, their movements, and their technological innovations. There are many reasons for this. Kingdoms and empires, the central units of control in the ancient world, could only be maintained through military force. Due to limited agricultural ability, there were relatively few areas that could support large communities, so fighting was common.

Weapons and armor, designed to be sturdy, tended to last longer than other artifacts, and thus a great deal of surviving artifacts recovered tend to fall in this category as they are more likely to survive. Weapons and armor were also mass-produced to a scale that makes them quite plentiful throughout history, and thus more likely to be found in archaeological digs.

Such items were also considered signs of prosperity or virtue, and thus were likely to placed in tombs and monuments to prominent warriors. And writing, when it existed, was often used for kings to boast of military conquests or victories.

Writing, when used by the common man, also tended to record such events, as major battles and conquests constituted major events that many would have considered worthy of recording either in an epic such as the Homeric writings pertaining to the Trojan War, or even personal writings. Indeed the earliest stories center on warfare, as war was both a common and dramatic aspect of life; the witnessing of a major battle involving many thousands of soldiers would be quite a spectacle, even today, and thus considered worthy both of being recorded in song and art, but also in realistic histories, as well as being a central element in a fictional work.

Lastly, as nation states evolved and empires grew, the increased need for order and efficiency lead to an increase in the number of records and writings. Officials and armies would have good reason for keeping detailed records and accounts involving any and all things concerning a matter such as warfare that in the words of Sun Tzu was "a matter of vital importance to the state". For all these reasons, military history comprises a large part of ancient history.

In China, the Shang Dynasty and Zhou Dynasty had risen and collapsed. This led to a Warring States period, in which several states continued to fight with each other over territory. Philosopher-strategists such as Confucius and Sun Tzu wrote various manuscripts on ancient warfare (as well as international diplomacy).

The Warring States era philosopher Mozi (Micius) and his Mohist followers invented various siege weapons and siegecraft, including the Cloud Ladder (a four-wheeled, extendable ramp) to scale fortified walls during a siege of an enemy city. The warring states were first unified by Qin Shi Huang after a series of military conquests, creating the first empire in China.

His empire was succeeded by the Han Dynasty, which expanded into Central Asia, Northern China/Manchuria, Southern China, and present day Korea and Vietnam. The Han came into conflict with settled people such as the Wiman Joseon, and proto-Vietnamese Nanyue. They also came into conflict with the Xiongnu (Huns), Yuezhi, and other steppe civilizations.

The Han defeated and drove the Xiongnus west, securing the city-states along the silk route that continued into the Parthian Empire. After the decline of central imperial authority, the Han Dynasty collapsed into an era of civil war and continuous warfare during the Three Kingdoms period in the 3rd century AD.

The Peloponnesian War then erupted between the two Greek powers Athens and Sparta. Athens built a long wall to protect its inhabitants, but the wall helped to facilitate the spread of a plague that killed about 30,000 Athenians, including Pericles. After a disastrous campaign against Syracuse, the Athenian navy was decisively defeated by Lysander at the Battle of Aegospotami.

The Macedonians, underneath Philip II of Macedon and Alexander the Great, invaded Persia and won several major victories, establishing Macedonia as a major power. However, following Alexander's death at an early age, the empire quickly fell apart.

In 54 BC the Roman triumvir Marcus Licinius Crassus took the offensive against the Parthian Empire in the east. In a decisive battle at Carrhae Romans were defeated and the golden Aquilae (legionary battle standards) were taken as trophies to Ctesiphon. The battle was one of the worst defeats suffered by the Roman Republic in its entire history.

While successfully dealing with foreign opponents, Rome experienced numerous civil wars, notably the power struggles of Roman generals such as Marius and Sulla during the end of the Republic. Caesar was also notable for his role in the civil war against the other member of the Triumvirate (Pompey) and against the Roman Senate.

The successors of Caesar – Octavian and Mark Anthony, also fought a civil war with Caesar's assassins (Senators Brutus, Cassius, etc.). Octavian and Mark Anthony eventually fought another civil war between themselves to determine the sole ruler of Rome. Octavian emerged victorious and Rome was turned into an empire with a huge standing army of professional soldiers.

By the time of Marcus Aurelius, the Romans had expanded to the Atlantic Ocean in the west and to Mesopotamia in the east and controlled Northern Africa and Central Europe up to the Black Sea. However, Aurelius marked the end of the Five Good Emperors, and Rome quickly fell into decline.

When stirrups came into use some time during the Dark Ages militaries were forever changed. This invention coupled with technological, cultural, and social developments had forced a dramatic transformation in the character of warfare from antiquity, changing military tactics and the role of cavalry and artillery.

Similar patterns of warfare existed in other parts of the world. In China around the 5th century armies moved from massed infantry to cavalry based forces, copying the steppenomads. The Middle East and North Africa used similar, if often more advanced, technologies than Europe.

In Japan the Medieval warfare period is considered by many to have stretched into the 19th century. In Africa along the Sahel and Sudan states like the Kingdom of Sennar and Fulani Empire employed Medieval tactics and weapons well after they had been supplanted in Europe.

In the Medieval period, feudalism was firmly implanted, and there existed many landlords in Europe. Landlords often owned castles to protect their territory.

In China, the Sui Dynasty had risen and conquered the Chen Dynasty of the south. They invaded Vietnam (northern Vietnam had been in Chinese control since the Han Dynasty), fighting the troops of Champa, who had cavalry mounted on elephants. After decades of economic turmoil and a failed invasion of Korea, the Sui collapsed and was followed by the Tang Dynasty, who fought with various Turkic groups, the Tibetans of Lhasa, the Tanguts, the Khitans, and collapsed due to political fragmentation of powerful regional military governors (jiedushi). The innovative Song Dynasty followed next, inventing new weapons of war that employed the use of Greek Fire and gunpowder (see section below) against enemies such as the Jurchens.

The Mongols under Genghis Khan, Ögedei Khan, Möngke Khan, and Kublai Khan conquered most of Eurasia. They took over China, Persia, Turkestan, and Russia. After Kublai Khan took power and created the Yuan Dynasty, the divisions of the empire ceased to cooperate with each other, and the Mongol Empire was only nominally united.

In New Zealand, prior to European discovery, oral histories, legends and whakapapa include many stories of battles and wars. Māori warriors were held in high esteem. One group of Polynesians migrated to the Chatham Islands, where they developed the largely pacifist Moriori culture. Their pacifism left the Moriori unable to defend themselves when the islands were invaded by mainland Māori in the 1830s.

They proceeded to massacre the Moriori and enslave the survivors.[19][20]Warrior culture also developed in the isolated Hawaiian Islands. During the 1780s and 1790s the chiefs and alii were constantly fighting for power. After a series of battles the Hawaiian Islands were united for the first time under a single ruler who would become known as Kamehameha I.

This all brought an end to the dominance of armored cavalry on the battlefield. The simultaneous decline of the feudal system – and the absorption of the medieval city-states into larger states – allowed the creation of professional standing armies to replace the feudal levies and mercenaries that had been the standard military component of the Middle Ages.

The period spanning between the 1648 Peace of Westphalia and the 1789 French Revolution is also known as Kabinettskriege (Princes' warfare) as wars were mainly carried out by imperial or monarchics states, decided by cabinets and limited in scope and in their aims. They also involved quickly shifting alliances, and mainly used mercenaries.

Over the course of the 18th-19th centuries all military arms and services underwent significant developments that included a more mobile field artillery, the transition from use of battalion infantry drill in close order to open order formations and the transfer of emphasis from the use of bayonets to the rifle that replaced the musket, and virtual replacement of all types of cavalry with the universal dragoons, or mounted infantry.

As weapons—particularly small arms—became easier to use, countries began to abandon a complete reliance on professional soldiers in favor of conscription. Technological advances became increasingly important; while the armies of the previous period had usually had similar weapons, the industrial age saw encounters such as the Battle of Sadowa, in which possession of a more advanced technology played a decisive role in the outcome.

Conscription was employed in industrial warfare to increase the number of military personnel that were available for combat. This was used by Napoleon Bonaparte in the Napoleonic Wars.

In modern times, war has evolved from an activity steeped in tradition to a scientific enterprise where success is valued above methods. The notion of total war is the extreme of this trend.[citation needed] Militaries have developed technological advances rivaling the scientific accomplishments of any other field of study.[citation needed]

However, it should be noted that modern militaries benefit in the development of these technologies under the funding of the public, the leadership of national governments, and often in cooperation with large civilian groups, such as the General Dynamics and Lockheed Martin corporations, in the United States. And as for "total war", it may be argued that it is not an exclusive practice of modern militaries, but in the tradition of genocidal conflict that marks even tribal warfare to this day.[citation needed]

What distinguishes modern military organizations from those previous is not their willingness to prevail in conflict by any method, but rather the technological variety of tools and methods available to modern battlefield commanders, from submarines to satellites, from knives to nuclear warheads.

Some of the military unit types and technologies which were developed in modern times are:

Major operations by the Germans at the Battle of Verdun and by the British and the French at the Battle of the Somme were carried out, and new technology like tanks and chlorine gas were used. Following the USA's entrance into the war, the Germans and their allies were eventually defeated.

World War II ensued after Germany's invasion of Poland, forcing Britain and France to declare war. Germany quickly defeated France and Belgium, later aided by Italy. A hasty evacuation occurred at Dunkirk to save the Allied army from complete destruction. The Germans then attacked the USSR and marched to take over the Soviet resources, but were thwarted.

Meanwhile, Japan, who had already been at war with the Chinese since 1937, had launched a surprise attack on Pearl Harbor, leading the United States to join the Allied powers. In Europe, the Allies opened three fronts: in the west, after securing Normandy; in the east, aiding the Soviet Union; and in the south, through Italy. Germany eventually surrendered, upon which the Allies turned and focused troops to do island hopping. The dropping of the atom bombs on Hiroshima and Nagasaki led to the surrender of Japan and the end of the Second World War.

Grimsley, Mark. "Why Military History Sucks", Nov. 1996, War Historian.org, online at [1]

Karsten, Peter. "The 'New' American Military History: A Map of the Territory, Explored and Unexplored", American Quarterly, 36 #3, (1984), 389–418 in JSTOR

Kohn, Richard H. "The Social History of the American Soldier: A Review and Prospectus for Research", American Historical Review, 86 (June 1981), 553–67. in JSTOR

Lee, Wayne E. "Mind and Matter—Cultural Analysis in American Military History: A Look at the State of the Field", Journal of American History, 93 (March 2007), 1116–42. Fulltext: History Cooperative and Ebsco

Lynn, John A. "Rally Once Again: The Embattled Future of Academic Military History", Journal of Military History, 61 (Oct. 1997), 777–89.

Mearsheimer, John J. Liddell Hart and the Weight of History. (1988). 234 pp.